package server;

import org.dom4j.*;
import org.dom4j.io.SAXReader;

import java.io.*;
import java.lang.reflect.InvocationTargetException;
import java.net.*;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * Minicat的主类
 */
public class Bootstrap {

    /** 定义socket监听的端口号 */
    private int port = 8080;
    private String appBase;

    private Mapper mapper;

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }

    /**
     * Minicat启动需要初始化展开的一些操作
     */
    public void start() throws Exception {

        loadServer();

        loadWebapps();

        // 加载解析相关的配置，web.xml
//        loadServlet();

        // 定义一个线程池
        int corePoolSize = 10;
        int maximumPoolSize = 50;
        long keepAliveTime = 100L;
        TimeUnit unit = TimeUnit.SECONDS;
        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(50);
        ThreadFactory threadFactory = Executors.defaultThreadFactory();
        RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();

        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(corePoolSize, maximumPoolSize, keepAliveTime,
            unit, workQueue, threadFactory, handler);

        /*
            完成Minicat 1.0版本
            需求：浏览器请求http://localhost:8080,返回一个固定的字符串到页面"Hello Minicat!"
         */
        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("=====>>>Minicat start on port：" + port);

        /*while(true) {
            Socket socket = serverSocket.accept();
            // 有了socket，接收到请求，获取输出流
            OutputStream outputStream = socket.getOutputStream();
            String data = "Hello Minicat!";
            String responseText = HttpProtocolUtil.getHttpHeader200(data.getBytes().length) + data;
            outputStream.write(responseText.getBytes());
            socket.close();
        }*/

        /**
         * 完成Minicat 2.0版本 需求：封装Request和Response对象，返回html静态资源文件
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();
        
            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());
        
            response.outputHtml(request.getUrl());
            socket.close();
        
        }*/

        /**
         * 完成Minicat 3.0版本 需求：可以请求动态资源（Servlet）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();
        
            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());
        
            // 静态资源处理
            if(servletMap.get(request.getUrl()) == null) {
                response.outputHtml(request.getUrl());
            }else{
                // 动态资源servlet请求
                HttpServlet httpServlet = servletMap.get(request.getUrl());
                httpServlet.service(request,response);
            }
        
            socket.close();
        
        }
        */

        /*
            多线程改造（不使用线程池）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            requestProcessor.start();
        }*/

        System.out.println("=========>>>>>>使用线程池进行多线程改造");
        /*
            多线程改造（使用线程池）
         */
        while (true) {

            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket, mapper);
            // requestProcessor.start();
            threadPoolExecutor.execute(requestProcessor);
        }

    }

    // 读取server.xml
    private void loadServer() {
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("server.xml");
        SAXReader saxReader = new SAXReader();

        try {
            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            // 读取端口
            Element connectorElement = (Element)rootElement.selectSingleNode("/Server/Service/Connector");
            Attribute portAtt = connectorElement.attribute("port");
            port = Integer.parseInt(String.valueOf(portAtt.getData()));

            // 读取webapps目录
            Element hostElement = (Element)rootElement.selectSingleNode("/Server/Service/Engine/Host");
            Attribute appBaseAtt = hostElement.attribute("appBase");
            appBase = String.valueOf(appBaseAtt.getData());

            mapper = new Mapper();

        } catch (DocumentException e) {
            e.printStackTrace();
        }
    }

    private void loadWebapps() throws FileNotFoundException, MalformedURLException, ClassNotFoundException {
        // 获取webapps路径
        File webappsFile = new File(appBase);

        if (!webappsFile.exists() || webappsFile.isFile()) {
            return;
        }

        File[] webapps = webappsFile.listFiles();

        // 读取webapps里的demo1 demo2
        if (webapps.length > 0) {
            for (File webapp : webapps) {
                if (webapp.isFile()) {
                    continue;
                }
                String path = webapp.getPath();
                String webappName = webapp.getName();

                // 用URLClassLoader读取指定目录下的class
                URLClassLoader urlClassLoader = new URLClassLoader(new URL[] {new URL("file:" + path+"/")});
                InputStream inputStream = urlClassLoader.getResourceAsStream("web.xml");
                doLoadServlet(urlClassLoader, inputStream, webappName);

            }
        }

    }

    /**
     * 加载解析web.xml，初始化Servlet
     */
//    private void loadServlet() {
//        ClassLoader classLoader = this.getClass().getClassLoader();
//        InputStream resourceAsStream = classLoader.getResourceAsStream("web.xml");
//
//        doLoadServlet(classLoader, resourceAsStream, null);
//    }

    private void doLoadServlet(ClassLoader classLoader, InputStream inputStream, String webappName) {
        SAXReader saxReader = new SAXReader();

        try {
            Document document = saxReader.read(inputStream);
            Element rootElement = document.getRootElement();

            List<Element> selectNodes = rootElement.selectNodes("//servlet");
            for (int i = 0; i < selectNodes.size(); i++) {
                Element element = selectNodes.get(i);
                // <servlet-name>lagou</servlet-name>
                Element servletnameElement = (Element)element.selectSingleNode("servlet-name");
                String servletName = servletnameElement.getStringValue();
                // <servlet-class>server.LagouServlet</servlet-class>
                Element servletclassElement = (Element)element.selectSingleNode("servlet-class");
                String servletClass = servletclassElement.getStringValue();

                // 根据servlet-name的值找到url-pattern
                Element servletMapping = (Element)rootElement
                    .selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                // /lagou
                String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();

                if (webappName != null && webappName != " ") {
                    urlPattern = "/" + webappName + urlPattern;
                }
                Class<?> aClass = classLoader.loadClass(servletClass);

                //组装到Mapper
                Wrapper wrapper = new Wrapper();
                wrapper.setServlet((HttpServlet)aClass.getDeclaredConstructor().newInstance());
                wrapper.setUrlPattern(urlPattern);
                Context context = new Context();
                context.addWrapper(wrapper);
                context.setContextName(webappName);
                mapper.getHost().addContext(context);

            }

        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
    }

    /**
     * Minicat 的程序启动入口
     * 
     * @param args
     */
    public static void main(String[] args) {
        Bootstrap bootstrap = new Bootstrap();
        try {
            // 启动Minicat
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
